Excited State Spectroscopy in Carbon Nanotube Double Quantum Dots

Sapmaz, Sami; Meyer, Carola; Beliczynski, Piotr; Jarillo‐Herrero, Pablo; Kouwenhoven, Leo P.

doi:10.1021/nl052498e

Cited by 74 publications

(78 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A new fabrication technique has been used for the top gates (TGs) in order to avoid covering the whole nanotube with an oxide layer. The TGs allow us to form single dots and control the coupling between them [49]. We observe four-fold shell filling and excited states in the DQD, a necessary step for determining the spin and orbital relaxation times.…”

Section: Excited States In Carbon Nanotube Double Quantum Dotsmentioning

confidence: 99%

“…By applying positive voltages to the top gates, we form barriers in the p-type region and can form single dots on both the left and right CNT segments individually (see figure 3). The energy level spacing, , we extract corresponds to the length of the CNT between top gates [49]. Figure 14(a) shows the characteristic 'honeycomb' structure of the current through a DQD [56] in the strongly coupled regime.…”

Section: Excited States In Carbon Nanotube Double Quantum Dotsmentioning

confidence: 99%

See 1 more Smart Citation

Quantum dots in carbon nanotubes

Sapmaz

Jarillo‐Herrero

Kouwenhoven

et al. 2006

Semicond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

In this overview paper, we present low-temperature electronic transport measurements of carbon nanotube quantum dots with a back gate. In a semiconducting tube, charge carriers could be completely depleted. The addition energy and the excitation spectrum have been studied as a function of the number of charges (electrons or holes), one by one. We observe electron-hole symmetry, which is a direct consequence of the symmetric band structure of the nanotube. The excitation spectrum for metallic nanotubes exhibits four-fold shell filling and is completely described by an extended constant-interaction model. Furthermore, nanotubes with a four-fold shell structure are investigated in a parallel magnetic field. The magnetic field induces a large splitting between the two orbital states of each shell, demonstrating their opposite magnetic moment and determining transitions in the spin and orbital configuration of the quantum dot ground state. Also, a small coupling is found between orbitals with opposite magnetic moments leading to anti-crossing behaviour at zero field. Current-voltage characteristics of suspended carbon nanotube quantum dots show an additional series of steps equally spaced in voltage. The energy scale of this harmonic, low-energy excitation spectrum is consistent with that of the longitudinal low-k phonon mode (stretching mode) in the nanotube. Finally, we report on a fully tunable carbon nanotube double quantum dot. We perform inelastic transport spectroscopy via the excited states in the double quantum dot, a necessary step towards the implementation of new microwave-based experiments for quantum information technology.

show abstract

Section: Excited States In Carbon Nanotube Double Quantum Dotsmentioning

confidence: 99%

Section: Excited States In Carbon Nanotube Double Quantum Dotsmentioning

confidence: 99%

Quantum dots in carbon nanotubes

Sapmaz

Jarillo‐Herrero

Kouwenhoven

et al. 2006

Semicond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the range V g1 > 1.5 V, hexagonal patterns are clearly evident. Current along all hexagon boundaries is finite, indicating that the system is in a strongly coupled regime, and the two dots interact by quantum-mechanical tunnel coupling, analogous to coupling by covalent bonding in a two-atom molecule [27][28][29].…”

Section: Electrical Propertiesmentioning

confidence: 99%

Fabrication of quantum-dot devices in graphene

Moriyama

Morita

Watanabe³

et al. 2010

Science and Technology of Advanced Materials

View full text Add to dashboard Cite

We describe our recent experimental results on the fabrication of quantum-dot devices in a graphene-based two-dimensional system. Graphene samples were prepared by micromechanical cleavage of graphite crystals on a SiO 2 /Si substrate. We performed micro-Raman spectroscopy measurements to determine the number of layers of graphene flakes during the device fabrication process. By applying a nanofabrication process to the identified graphene flakes, we prepared a double-quantum-dot device structure comprising two lateral quantum dots coupled in series. Measurements of low-temperature electrical transport show the device to be a series-coupled double-dot system with varied interdot tunnel coupling, the strength of which changes continuously and non-monotonically as a function of gate voltage.

show abstract

“…Owing to good electrical conductivity and lack of impurities and net nuclear spin, the electron charge and spin states in gate-defined CNT quantum dots (QDs) [4][5][6][7][8] are promising candidates for solid-state quantum information processing. However, a scalable quantum processor requires long-range couplings, which is a challenge for QDs, because there are only local interactions between neighboring QDs.…”

Section: Introductionmentioning

confidence: 99%

Strongly Coupled Nanotube Electromechanical Resonators

et al. 2016

View full text Add to dashboard Cite

Coupling an electromechanical resonator with carbon-nanotube quantum dots is a significant method to control both the electronic charge and the spin quantum states. By exploiting a novel micro-transfer technique, we fabricate two strongly-coupled and electrically-tunable mechanical resonators on a single carbon nanotube for the first time. The frequency of the two resonators can be individually tuned by the bottom gates, and strong coupling is observed between the charge states and phonon modes of each resonator. Furthermore, the conductance of either resonator can be nonlocally modulated by the phonon modes in the other resonator. Strong coupling is observed between the phonon modes of the two resonators, which provides an effective long distance electron-electron interaction. The generation of phonon-mediated-spin entanglement is also analyzed for the two resonators. This strongly-coupled nanotube electromechanical resonator array provides an experimental platform for studying the coherent electron-phonon interaction, the phonon mediated long-distance electron interaction, and entanglement state generation.

show abstract

Excited State Spectroscopy in Carbon Nanotube Double Quantum Dots

Cited by 74 publications

References 31 publications

Quantum dots in carbon nanotubes

Quantum dots in carbon nanotubes

Fabrication of quantum-dot devices in graphene

Strongly Coupled Nanotube Electromechanical Resonators

Contact Info

Product

Resources

About